Storage systems provide data storage for computer systems. Attached storage systems allow storage devices to be attached to computer systems for use. Direct-attached storage (DAS) refers to a storage system directly attached to a computer system without a storage network in between. Network-attached storage (NAS) is a file-level computer data storage connected to a computer network providing data access to heterogeneous network clients of a computer system. A storage area network (SAN) is an architecture to attach remote computer storage devices (such as disk arrays, tape libraries, and optical jukeboxes) to servers so as to appear locally attached to the computer system.